1. Field of the Invention
The present invention relates generally to pigmentation supplements for animal feed compositions, and more particularly to the use of comminuted Haematococcus alga as a pigmentation supplement in compositions for feeding aquatic and other animals.
The cultivation of marine animals, including fish, crustaceans, and the like has become increasingly important with the over-harvesting of natural marine habitats and the growth of the world consumption of these animals. As this cultivation is typically performed in limited areas, such as isolated ponds and estuaries, and at high population densities, it is necessary to provide artificial food sources to supplement whatever natural food sources may be present. To the extent possible, the artificial food sources should mimic the natural food sources so that the cultivated animal product closely resembles the naturally-harvested animal product.
The present invention is concerned primarily with one aspect of such artificial food sources, i.e., the provision of a pigmentation source for naturally pigmented animals such as salmon, trout, shrimp, lobster, chickens, and the like. Such animals, which generally have yellow, orange, and red pigmentation, derive their natural pigmentation from a variety of carotenoids, such as beta-carotene, canthaxanthin, zeaxanthin, astaxanthin, astaxanthin ester, and the like. Of particular interest in preparing artificial food sources is astaxanthin which provides a source of pigmentation in a wide variety of aquatic animals, often without the need for the animal to biologically convert the astaxanthin to any other form of carotenoid.
While astaxanthins are highly successful in providing a natural-appearing pigmentation in a wide variety of animals, natural astaxanthins are limited in availability and synthetic astaxanthins are difficult and costly to prepare. It would therefore be desirable to provide astaxanthin-containing feed supplements which may be produced in large quantities at relatively low cost. Such feed supplements should be effective in enhancing pigmentation of the animal receiving the supplement, should be free from toxicity, and should be storable for relatively long periods of time.
2. Description of the Background Art
Simpson et al. (1981), in: "Carotenoid as Colorants and Vitamin A Precursors" (Bauernfiend, ed.), pp. 463-538, Academic Press, New York, N.Y., references the incorporation of various carotenoids, including astaxanthins, in fish feeds in order to enhance pigmentation. Nakazoe and Hata (1978) Proc. Jpn. Soc. Sci. Fish., 53rd Meet., Tokyo, Abstract No. 558 (cited in Simpson et al. at page 528), describes the feeding of pressed, cellulase-treated Haematococcus to enhance the coloration of Chrysophyrs major. Although an increase in red coloration was reported, the authors noted that the Haematococcus treatment method required improvement. Pringsheim (1966) Phycol. 2:1-7, describes the nutritional requirements of Haematococcus pluvialis. Droop (1955) Arkiv. fur Mikrobiologie 21:267-272, describes the factors governing encystment in Haematococcus pluvialis. The biosynthesis of carotenoids by Haematococcus pluvialis is discussed in Goodwin and Jamikorn (1954) J. Biochem. 57:376-381; Droop (1955) Nature 175:42; and Donkin (1976) Phytochemistry 15:711-715.